Thread-controlling mechanism for sewing-machines.



W. P. DRUMHELLER THREAD CONTROLLING MECHANISM FOR SEWING M'ACHIN APPLICATION FILED JULY 29.1916.

3 SHEETS-SHEET I.

Patented July 17, 1917.

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APPLICATION FILEDJULY 29,1916- Patented July 17, 1917.

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APPLICATION FILED JULY 29, I916.

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WILLIAM P. DRUMHELLER, OF SPRINGFIELD, MASSACHUSETTS, ASSIGNOR TO THE WILLIAM CARTER COMPANY, OF NEEDHAM, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

THREAD-CONTROLLING MECHANISM FOR SEWING-MACHINES.

To all whom it may concern:

Be it known that I, l/VILLIAM P. DRUM- HELLER, a. citizen of the United States, and a resident of Springfield, in the county of Hampden and State ofMassachusetts, have invented an Improvementin Thread-Controlling Mechanism for Sewing-Machines, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention relates to thread controlling mechanism for sewing machines, and particularly to sewing machines of the double locked-stitch type.

In, order that the principle of the inventionmay be readily understood, I have disclosed a single embodiment thereof in the accompanying drawings, wherein- Figure 1 is a side elevation of so much of a sewing machine as is necessary to an understanding of my invention;

Fig. 2 is a perspective view showing the thread controlling means;

Fig. 3 is an end elevation of the construc-v tion shown in Fig. 1; and

The remaining figures indicate in a series of views the different positions of the parts during one complete cycle of movement.

WhiIe my invention is in no wise limited thereto, it is particularly adapted to that type of sewing machine shown in the United States patent to R. G. l/Voodward, No. 615,647, dated December 6, 1898.

It has heretofore been proposed to control the looper thread and to take up the slack thereof, but so far as I am aware the results have not been wholly satisfactory, nor has a very tight, flat seam been formed by the mechanisms of which I am aware. In accordance with my invention, I not only take up the slack thread, but I apply tension thereto, preferably as the looper starts to move forward and throughout most of its forward movement, and again as the looper starts to move back and throughout most, if not all, of its said. backward movement. Heretofore there has been great liability of the looper thread becoming slack, and in such event one or more of the needle threads,

which are positioned tightly about the looper catch the looper thread and pull it underneath or onto the reverse side of the looper, thus causing the dropping of a stitch. It

Specification of Letters Patent.

Application filed July 29, 1916. I

Patented July 17, 1917.

Serial No. 112,124.

suitably tensioned when and during the most of the time that the looper is moving back, then when the looper moves forward again, so much slack exists that the usual take-up means cannot take care of all the slack and the stitch is dropped. I have overcome these and other disadvantages by the invention herein disclosed.

Referring more particularly to the drawings and first to the construction shown in Figs. 1, 2 and 3, a portion of the standard of the sewing machine is represented at 1 in Figs. 1 and 3, the cylindrical casing is represented at 2 and the three needles at 3, 4 and 5. In conjunction with said needles, I employ two flier threads which move to and fro at the upper side of the seam. The fliers therefor are diagrammatically indicated at 6 and 7. The looper is indicated in the several views at 8, the shaft on which it i secured is indicated at 9, and the looper guard finger is indicated at 10. Upon the side of the standard is secured a suitable box or frame 11, in which the take-up and tensioning devices are supported, the said parts being fast upon the end of the main shaft 12 of the machine, said shaft being journaled in suitable hearings in the standard 1. Upon the lug 13 extending from the box or frame 11 may be supported a suitable tension (not herein shown) and through which the thread supplying the looper is led from the spool.

Upon the main shaft 12 is a thread take-v up device comprising a rotary cam disk 1 1 having formed thereon two cam surfaces 15, 16, which are preferably of equal radial ex tent and of the proportional peripheral eX- tent indicated in the diagrammatic views, Figs. 4 to 8, wherein the said cam is shown as of actual size. The cam 15 acts as a takeup for the looper thread when the looper is moving forward and the cam 16 acts as a take-up therefor when the looper is moving back. The said cam disk with its two cam surfaces is provided with a groove 17 in which the stationary throw-out arm 18 rests, guides 19, 20 being provided upon either side of the cam disk to compel the thread to ride over the edges of the disk. An arm 21 is also preferably provided to hold the thread on the cam surface.

Between the cam disk 14 and the source of supply of the looper thread I position a thread tensioning device, herein represented as a cam disk 22 mounted upon the said main shaft having two cam portions 23, 2a of equal or substantially equal radial extent and preferably of equal circumferential extent. Said tension cam 22 co-acts with any suitable device to act directly upon the looper thread and heroin represented as two nipper springs 25, 26, which are caused twice in the rotation of the said cam 22 to nip the thread and thereby tension the same. The construction and relation of parts are such that the looper thread is thereby ten- 7 it will be observed that there is no tension sioned substantially just as the looper starts to vmove forward, such tension continuing until the looper has nearly reached its forward position. The tension is then withdrawn, but is re-instituted about as the looper starts to move back and continues until the looper is nearly back. In Figs. l to 13 inclusive, 'I have represented a series of diagrammatic views illustrating one complete cycle of operations, said figures being designated a, 434", 5,52 5 etc. In Figs. at, 4: and 4t, and Fig. 9, wherein the looper is at its extreme backward limit of movement,

imparted to the thread by the cam 22 and that no take-up of the thread occurs through the action of the cam let. Thesefacts are indicatedby the straight course of the thread in'Fig. 9.

In Figs. 5, 5, 5 and in Fig. 10, the looper is represented as moving forward, but not yet at its extreme limit of forward movement. The positions of the cams 14, 22 in' said figures are such that the tension is imparted tothe looper thread by the cam 22, and that between the cam 22 and the looper the slack in the thread is taken up by the cam .14. The irregular course of the thread in Fig. 10 indicates take-up thereof and the double-headed arrow indicates that no thread is being drawn through.

. In Figs. 6, 6, 6 and 11, the looper is represented as at its extreme forward position and at such time the cams 14C and 22' release the looper thread, so that the same is neither under tension nor is there any take-up thereof, but the take-up is ust about to commence.

In Figs. 7, 7, 7 and 12, the looper isrepresented as moving backward, and therein the position'of the cams 14 and 22 is such that the threadis tensioned and theslack thereof is taken up, the take-up being inclicated' by the irregular course of the thread Fig. 12.

In Figs. 8, 8, 8 and 13, the looper is represented as'nearing its extreme backward position, and in such position the tension upon the looper yarn continues, but at that be made double and acts twice during each upward movement of the looper, cannot take the entireslackage of the thread, and a stitch is dropped.

The looper thread customarily lies in a groove along one face of the looper and extends thence to the cloth. When the looper moves forward, tension is applied, inasmuch as the three needle threads are wrapped in the bight about the looper, and if the looper thread were not taut at such time, the needle threads, when the needles start their upward movement, being tightly wrapped about the looper, would pull on the looper thread and withdraw it from its position in its 2 groove, causing so much slack that when the looper is at its extreme forward movement and is about to start back, all the slack of the thread cannot be taken up with thread controlling mechanism with which I am aware.

The result of tensioning the thread as described is not only to prevent dropping of the stitches, but to effect the sewing of a very tight fiat seam. In the formation of such seam and as the three needles move upwardly, the two fly threads, the controlling fliers whereof are diagrammatically indicated at 6 and 7, cross each other and re-cross while the needles are down.

Having thus described one illustrative embodiment of my invention, I desire it to be understood that although specific terms are employed, they are used in a generic and descriptive sense and not for purposes of limitation, the scope of the invention being set forth in the following claims.

Claims:

1. Thread controlling mechanism for sewing machines comprising in combination one or more sewing needles, a looper, means to impart forward and backward movements to said looper, and means to apply tension to the looper thread as the looper starts forward and throughout most of its forward movement.

2. Thread controlling mechanism for sewing machines comprising in combination, one or more sewing needles, a looper, means to impart forward and backward movements to said looper, means to apply tension to the looper thread substantially when the looper commences its backward movement and continuing until such backward movement has nearly terminated and means to apply tension to the looper thread, throughout most of the forward movement of the looper. I

3. Thread controlling mechanism for sewing machines comprising in combination, one or more sewing needles, a looper, means to impart forward and backward movements to said looper, means to apply tension to the looper thread as the looper starts forward and throughout most of its forward movement, and means to take up the looper thread when the looper is moving. forward.

4:. Thread controlling mechanism for sewing machines comprising in combination,

one or more sewing needles, a looper, means to impart forward and backward movements to said looper, means to apply tension to the looper thread substantially when the looper commences its backward move ment and continuing until such backward movement has nearly terminated, and means to take up the looper thread when the looper is moving backward and means to apply tension to the looper thread throughout most of the forward movement of the looper.

5. Thread controlling mechanism for sewing machines comprising in combination, one or more sewing needles, a looper, means to impart forward and backward movements to said looper, and looper-thread tensioning means comprising the cam disk 22 having two cam portions 23, 24.

6. Thread controlling mechanism for sewing machines comprising in combination, one or more sewing needles, a looper, means to impart forward and backward movements to said looper, and means for applying tension to the looper thread comprising the cam disk 22 having the two cam portions 23, 24: of equal radial and circumferential extent.

7. Thread controlling mechanism for sewing machines comprising in combination, one or more sewing needles, a looper, means to impart forward and backward movements to said looper, and means to tension the looper thread substantially just as the looper starts to move forward.

8. Thread controlling mechanism for sewing machines comprising in combination, one or more sewing needles, a looper, means to impart forward and backward movements to said looper, and means to tension the looper thread substantially just as the looper starts to move forward and to continue such tensioning until the looper has nearly reached its forward position.

9. Thread controlling mechanism for sewing machines comprising in combination, one or more sewing needles, a looper, means to impart forward and backward movements to said looper, means to apply tension to the looper thread substantially when the looper commences its backward movement and means to apply tension to the looper thread substantially when the looper commences its forward movement.

10. Thread controlling mechanism for sewing machines comprising in combination,

one or more sewing needles, a looper, means to impart forward and backward movements to said looper,'means to apply tension to the looper thread substantially when the looper to impart forward and backward movements to said looper, and means to apply tension to the looper thread as the looper starts forward and throughout most of its forward movement, and also to apply tension as the looper starts backward and throughout most of its backward movement.

12. Thread controlling mechanism for sewing machines comprising in combination, oneor more sewing needles, a looper, means to impart forward and backward movements to said looper, and means to apply tension to the looper thread as the looper starts forward and throughout most of its forward movement, and also to apply tension as the looper starts backward and throughout most of its backward movement, said means including means to relieve the looper thread of tension when the looper is at its extreme forward limit of movement.

13. Mechanism for sewing a very flat, tight seam having crossed and recrossed threads comprising in combination, one or more sewing needles, a looper, means to impart forward and backward movements to said looper, means to apply tension to the looper thread as the looper starts forward and throughout most of its forward move ment, and means to lay flier threads obliquely across the upper face of the seam.

14. Mechanism for sewing a very flat, tight seam having obliquely laid threads upon its upper face comprising in combination, one or more sewing needles, a looper, means to impart forward and backward movements to said looper, means to a ply tension to the looper thread substantially when the looper commences its backward movement and continuing until such backward movement has nearly terminated, means to apply tension to the looper thread throughout most of the forward movement of the looper, and means to lay flier threads obliquely across the upper face of the seam.

15. Thread controlling mechanism for sewing machines comprising in combination one or more sewing needles, a looper, means to impart forward and backward movements to said looper, means to apply tension to the looper thread as the looper starts forward and throughout most of its forward movement, and a looper thread take-up device formed as a rotary cam having two cam projections of substantiallyequalradial extent, one of said projections being of slightly greater circumferential extent than the'o'ther.

16. Thread controlling mechanism for sewing machines comprising in combination,

one or more sewing needles, a looper, means to impart forward and backward movements to said looper, means to apply tension'to the lo'looper thread as the. looper commences its WILLIAM P. DRUMHELLER.

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